Corrosion of X52 steel under thin layers of water condensate in wet gas pipelines

Abstract

In this work, corrosion of an X52 pipeline steel in CO2-containing thin layers of solution was investigated. A model was proposed to illustrate the mechanistic aspect of internal corrosion of wet gas pipelines. The steel shows a “passive” behavior in CO2-containing thin layers of solution due to deposit of corrosion products. With the decrease of the solution layer thickness, the corrosion rate reduces, which is attributed to the protective effect of the products. The role of elevated temperature in the steel corrosion is dual, i.e., an accelerated corrosion reaction kinetics and the generation of a compact and homogeneous FeCO3 film to protect the steel from further corrosion. The presence of acetic acid in the carried wet gas usually increases the steel corrosion, but the effect becomes apparent at the elevated concentrations up to 500 and 1000 ppm. The methanol contained in the thin layers of solution would reduce corrosion rate of the steel.